<input type="text" id="key" name="key" value=" 请输入关键词" onFocus="if(value==defaultValue){value='';this.style.color='#000'}" onBlur="if(!value){value=defaultValue;this.style.color='#999'}"
style="color:#999999">
url:http://www.cnblogs.com/losesea/archive/2012/05/15/2501970.html